Hong Kong police have launched an internal investigation into a female officer who posted a video of herself dancing in uniform on mainland Chinese social media, and ordered her to remove it.The video, which has gone viral in recent days, shows a short-haired female constable making hand gestures and moving to upbeat music. Her face is partly obscured by a filter featuring dog ears and a muzzle.A police spokesman confirmed to the South China Morning Post that the woman in the video is a...